The Unintended Consequences of Changes to the Organ Allocation Policy
Authors: Richard N. Formica, Jesse D. Schold
Journal: Journal of the American Society of Nephrology (2023)

Organ allocation policies are particularly vulnerable to unintended consequences because of the role human behavior plays in the decision to accept an organ. Although unintended consequences can be theorized during the development process,1 attempts to avoid them may be incomplete or unsuccessful. More problematic is that the fear of them may cause resistance to change and paralysis of the policy-making process. Therefore, the best approach is to develop a policy with the available empirical evidence, use postimplementation monitoring to assess for the desired and undesired outcomes, and adjust it proactively. The 2014 kidney allocation system (KAS) provides an example of this approach. As demonstrated by KAS, policy changes may cause disequilibrium in the immediate postimplementation (bolus) period, which ultimately transitions to a desired steady state that reflects the policy's intended effect.2 Because of this, before judging a policy as having undesired outcomes, it is essential to ensure that the long-term effect of the policy is known. In this edition of JASN, Puttarajappa et al.3 report the initial outcomes of the first 9 months of kidney allocation under the revision to KAS that uses a 250-nm circle centered on the donor's location. Using the Scientific Registry of Transplant Recipients database, they report an early signal that the rate of kidney discards has increased following policy implementation. This is an important observation that warrants critical review; however, given many potential confounding factors, causation cannot be directly attributed to the effects of the policy, and the steady-state effects of policy may still be unclear. Additionally, it is important to recognize that the explicit intent of the policy was to reduce existing geographic disparities in access to kidney transplantation. The effect of the policy on attenuating geographic disparities was not assessed in this study. Therefore, the interpretation of potential unintended consequences of the policy should be considered in the context of the potential intended benefits, which will need to be assessed in prospective studies. The authors appropriately conclude that continued monitoring of the allocation policy for unintended negative consequences is required to develop strategies for improvement. The impetus to disseminate early observations is understandable given the potential effect of the policy and the need for timely data. However, the reader should also consider the immaturity of the policy when drawing inferences. Specifically, the results of prior allocation changes were reported after more extended periods of observation when the data indicated that equilibrium had been achieved.2,4,5 This observation aside, the authors also perform a rigorous sensitivity analysis addressing the limitations of the data available and the uncertainty of estimated effects. The reader is encouraged to consider the results carefully as well as other high-level observations when interpreting these findings. The 250-nm distribution plan for deceased donor kidneys was implemented during the severe acute respiratory syndrome coronavirus 2 pandemic and increased regulatory and media scrutiny on the practices of organ procurement organizations. Both events could influence organ allocation and affect organ utilization rates unrelated to the policy change. For example, the authors report that the new approach led to increased discards caused by "no candidate found." However, coronavirus disease may have led to this increase in discards by affecting candidate readiness for transplantation. Additionally, as the authors' data demonstrate, the increase in kidneys recovered came from donors after circulatory death. This increase in organ recovery is positive but likely due to organ procurement organizations more vigorously pursuing the recovery of donor organs, including donors after circulatory death, due to increased regulatory pressure. Given the expansion of the donor pool to include older and medically complex donors, it is reasonable to anticipate an increase in organ discards. As the system strives to recover as many organs as possible, it must also be acknowledged that more organs will be on the fringe of usability or not suitable for transplantation. Moreover, regardless of the observation of increased organ discard in this study, it is important to note that the total number of deceased donor transplants increased during the first year of the policy.6 The study reports 9 months of follow-up, which is unlikely enough time to characterize the steady-state effects of the policy. Kidney allocation uses a composite score of waiting time, human leukocyte antigen–DR matching, calculated panel-reactive antibody sliding scale points, and with the new policy, distance points. For the average allocation, waiting time is the major contributor to the score. By mandate, the new policy eliminates the boundaries of donor service areas (DSAs), which led to the existing differential waiting times. As a simplistic example, if adjacent DSAs had a 2-year difference in waiting time and waiting lists with the same composition and number of patients, it would take 1 year to reach a steady state. Patients in the DSA with longer waiting times would receive transplants, whereas those in the adjoining DSA would accumulate more waiting time until the waiting times equilibrated. At equilibrium, the variable determining the allocation would be distance points. Applying the principles of this example to areas with multiple adjacent DSAs, the expectation of >2 years to achieve a steady state is reasonable. Although the analysis of Puttarajappa et al.3 does not yet provide sufficient evidence to revise policy, it does compel the transplant community to critically consider the optimal balance between equity and efficiency in allocation policy. This study highlights potential early growing pains of the policy, and the extent to which geographic equity has been achieved will be important to complement these analyses. Although system efficiencies may be improved, it is also expected that broader sharing of organs leads to longer distances traveled and loss of organ viability. This reality necessitates critical questioning of appropriate trade-offs and requires ongoing thoughtful discussion. At what point are the improvements in equity gained through the broader sharing of organs offset by the need to minimize discards? In a system of constrained resources, can equity—offering the opportunity for transplantation to as many people as possible—be achieved without sacrificing efficiency—making use of as many donated organs as possible? This is the challenge before the transplant community as it attempts to reconcile its dual fiduciary roles to the individual patient and the larger society it serves, which may not always align. Stated succinctly, is it an absolute priority to ensure that every similarly situated patient with organ failure has an equal chance of accessing transplantation, or is this desirable only to the extent that it avoids significant donor organ loss? Although this statement is blunt, it is an important consideration in the context of the ongoing emphasis on equity in organ transplantation and is the question facing the transplant community as the model of continuous distribution of organs is implemented.7 Continuous distribution allows for candidate and organ-specific titration of equity and efficiency rather than the dichotomous trade-offs required with circles, DSA boundaries, or any categorical distance parameters. The mandate to eliminate DSA boundaries as the unit of allocation did not prescribe an alternative.8 Transplant policy makers take their direction from the National Organ Transplant Act and its rules for implementation: "the Final Rule."9,10 The legal directions are that allocation cannot be on the basis of a patient's place of residence but with qualifiers. The most notable of these qualifiers is to avoid organ wastage and promote system efficiency (Final Rule section 121.8a[8] and paragraphs [a1–a5]). Continuous distribution incorporates candidate needs, biologic factors, donor organ quality, and system efficiency to create an allocation score. This score is then overlaid on a distance scale to determine the rank order of candidates.11 Although these factors are all discrete, they are weighted in importance on the basis of community consensus. Continuous distribution does not use DSA as an allocation component; however, it does not need to be assumed that this framework requires sharing over an area >250 nm. It is possible that after implementing this approach in what is the most equitable way, postimplementation monitoring may reveal an increase in organ discards to an extent that is unacceptable. The community may respond by deciding that organs with certain characteristics should not be shared over such distances. This would conform with the Final Rule's instruction to avoid organ wastage and the requirement for equitable distribution. Additionally, the tension created by trying to minimize geographic disparities while minimizing organ wastage could incentivize investments and improvements in organ recovery and transportation. Unintended outcomes, whether short term or long term, provide the impetus for continuous improvement in organ allocation, and the fear of unintended outcomes should not paralyze the policy-making process.